FANCI phosphorylation functions as a molecular switch to turn on the Fanconi anemia pathway.
In response to DNA damage or replication fork stress, the Fanconi anemia pathway is activated, leading to monoubiquitination of FANCD2 and FANCI and their colocalization in foci. Here we show that, in the chicken DT40 cell system, multiple alanine-substitution mutations in six conserved and clustered Ser/Thr-Gln motifs of FANCI largely abrogate monoubiquitination and focus formation of both FANCI and FANCD2, resulting in loss of DNA repair function. Conversely, FANCI carrying phosphomimic mutations on the same six residues induces constitutive monoubiquitination and focus formation of FANCI and FANCD2, and protects against cell killing and chromosome breakage by DNA interstrand cross-linking agents. We propose that the multiple phosphorylation of FANCI serves as a molecular switch in activation of the Fanconi anemia pathway. Mutational analysis of putative phosphorylation sites in human FANCI indicates that this switch is evolutionarily conserved.
Ishiai
Masamichi
M
Laboratory of DNA Damage Signaling, Department of Late Effect Studies, Radiation Biology Center, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
Kitao
Hiroyuki
H
Smogorzewska
Agata
A
Tomida
Junya
J
Kinomura
Aiko
A
Uchida
Emi
E
Saberi
Alihossein
A
Kinoshita
Eiji
E
Kinoshita-Kikuta
Emiko
E
Koike
Tohru
T
Tashiro
Satoshi
S
Elledge
Stephen J
SJ
Takata
Minoru
M
D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D002110:Caffeine / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002645:Chickens; D004249:DNA Damage; D004252:DNA Mutational Analysis; D004260:DNA Repair; D005199:Fanconi Anemia / Q000378:metabolism*; D052236:Fanconi Anemia Complementation Group D2 Protein / Q000235:genetics / Q000378:metabolism; D051856:Fanconi Anemia Complementation Group Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D018716:Molecular Mimicry; D010726:Phosphodiesterase Inhibitors / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D025801:Ubiquitin / Q000378:metabolism
D018797:Cell Cycle Proteins; C519921:FANCI protein, human; D052236:Fanconi Anemia Complementation Group D2 Protein; D051856:Fanconi Anemia Complementation Group Proteins; D010726:Phosphodiesterase Inhibitors; D011993:Recombinant Fusion Proteins; D025801:Ubiquitin; D002110:Caffeine; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases